KENNEDY SPACE CENTER, FLA. - In the Space Station Processing Facility, workers help guide the Control Moment Gyroscope (CMG) as a crane lowers it onto the Small Adapter Plate Assembly. The CMG will be delivered to the International Space Station on Mission STS-114 aboard Space Shuttle Discovery to replace one that has failed. CMGs are critical to ISS operation, keeping the outpost properly oriented toward the Sun without the use of rocket fuel. Four CMGs are mounted inside a truss that extends upward from the Unity module?s zenith port. The Z1 truss, attached to the ISS during Mission STS-92 in October 2000, also carries the station?s main solar arrays. The launch window for Discovery is May 15 to June 3, 2005.